#define NPROC        64  // maximum number of processes
#define NCPU          8  // maximum number of CPUs
#define NOFILE       16  // open files per process
#define NFILE       100  // open files per system
#define NINODE       50  // maximum number of active i-nodes
#define NDEV         10  // maximum major device number
#define ROOTDEV       1  // device number of file system root disk
#define MAXARG       32  // max exec arguments
#define MAXOPBLOCKS  10  // max # of blocks any FS op writes 在文件和磁盘系统中，最多能写入的磁盘块数，用于确保一个文件不会太大
#define LOGSIZE      (MAXOPBLOCKS*3)  // max data blocks in on-disk log 磁盘日志中，最多可以包含的逻辑块数
#define NBUF         (MAXOPBLOCKS*3)  // size of disk block cache 磁盘块缓存可以容纳的磁盘块数
#define FSSIZE       2000  // size of file system in blocks
#define MAXPATH      128   // maximum file path name
